More photo memory

I've touched on this problem before. When you're writing over a period of time a character's looks and personality can be a bit fluid, so it helps to try to pin them down - tn makes for consistency from chapter to chapter.
A (vanilla) friend offered advice. He sticks pictures of people and places on a board in his office after the style of those walls you see in detective dramas. It's appropriate, as he's writing detective fiction.
Not so appropriate for me, of course. What would the pictures be - bottoms, underwear, inspiring implements of correction. My mother's pretty easy-going, but would not, I think, be amused.
Instead I've got a file on my laptop that is a sort of virtual picture wall. For 'A Month in the Country' the picture file got quite full, with images from tumblr and elsewhere that helped me visualise each of the main characters.

Flick, or Gemma

For example, my feisty heroine Flick ended up being represented in the photo file by the actress Gemma Arterton. In early chapters Flick had been a blonde, but as time went on I decided to make her the perfect English rose brunette - which had to be Gemma A.
Now I'm having trouble visualising my new heroine Beryl, or Bee, my 1940s Land Army girl. She's a sporty type who plays tennis and hockey, can handle hard farmwork and is also gorgeous enough to turn heads.
Perhaps she should be a redhead. Handprints work so well on very pale skin, don't they? So, whose picture should I put into the photo wall file? All, any, suggestions would be gratefully recieved.